How to solve the problem of under Windows pipes blocked?-CodePudding

The program is very simple:
Program A:
# include "stdio.h"
Int main ()
{
int index=0;
int i=0;
For (I=1; i <9988998; I++) {
Printf (" Current Count is % d \ n ", index++);

Sleep (10 * 999);
}
}

Would be stuck through pipeline access to stdout, investigate its reason, is because Windows stdout is fully buffered output, output only buffer is full, but I want to achieve A line will output A line, under the command line can be so, but the pipe has been not achieve them, search on the Internet A lot of code, though, asynchronous access, but also must to output after buffer is full, the question now is I can't modify A program, the above is just A example, the actual function more complicated than it, but the principle is same, also can't change the Windows command line to line buffer, everybody has what good method?

CodePudding user response:

Output a newline character, or brush the fflush function force can?

CodePudding user response:

Using PeekNamedPipe data query the pipeline, have read, no, don't read, main is to prevent the ReadFile congestion,

CodePudding user response:

Should be able to realize, similar to the back door binding the CMD rebound, the console input and output are taken over,

CodePudding user response:

reference 1st floor qq_36751214 response:

output a newline, or brush the fflush function force can?

I have no program a code, the code above is only for delay output function, actual output there is a delay, but the contents of the output and I write is not the same, it is useful to the data, I can do to modify the pipeline read program or modify the system registry

CodePudding user response:

Fyi:

 # pragma comment (lib, "user32") 
#include  
#include  
#include  
Int main () {
SECURITY_ATTRIBUTES sa={0}; 
STARTUPINFO si={0}; 
PROCESS_INFORMATION PI={0}; 
HANDLE hPipeOutputRead=NULL; 
HANDLE hPipeOutputWrite=NULL; 
HANDLE hPipeInputRead=NULL; 
HANDLE hPipeInputWrite=NULL; 
BOOL bTest=0; 
DWORD dwNumberOfBytesRead=0; 
DWORD dwNumberOfBytesWrite=0; 
CHAR szMsg [100]. 
CHAR szBuffer [256]. 

Sa. NLength=sizeof (sa); 
Sa. BInheritHandle=TRUE; 
Sa. The lpSecurityDescriptor=NULL; 

//Create pipe for standard output redirection. 
The CreatePipe (& amp; HPipeOutputRead,//read handle 
& HPipeOutputWrite,//write handle 
& Sa,//security attributes 
0//number of bytes reserved for pipe - 0, the default 
); 

//Create pipe for standard input redirection. 
The CreatePipe (& amp; HPipeInputRead,//read handle 
& HPipeInputWrite,//write handle 
& Sa,//security attributes 
0//number of bytes reserved for pipe - 0, the default 
); 

//Make the child process use hPipeOutputWrite as standard out, 
//and make sure it does not show on screen. 
Si. Cb=sizeof (si); 
Si. DwFlags=STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES; 
Si. WShowWindow=SW_HIDE; 
Si. HStdInput=hPipeInputRead; 
Si. HStdOutput=hPipeOutputWrite; 
Si. HStdError=hPipeOutputWrite; 

CreateProcess (
NULL, "CMD. Exe," 
NULL, NULL, 
TRUE, 0, 
NULL, NULL, 
& Si, & amp; PI); 

//Now that handles have had inherited, close it to be safe. 
//You don 't want to read or write to them accidentally. 
The CloseHandle (hPipeOutputWrite); 
The CloseHandle (hPipeInputRead); 

//Now test to capture the DOS application output by reading 
//hPipeOutputRead. Could also write the to DOS application 
//standard input by writing to hPipeInputWrite. 
Sprintf (szMsg, "ver \ n"); 
WriteFile (
HPipeInputWrite,//handle of the write end of our pipe 
& SzMsg,//address of buffer that send data 
Strlen (szMsg),//the number of bytes to write 
& DwNumberOfBytesWrite,//the address of the number of bytes read 
NULL//non - overlapped. 
); 

While (TRUE) 
{
BTest=ReadFile (
HPipeOutputRead,//handle of the read end of our pipe 
& SzBuffer,//the address of the buffer that receives the data 
256,//the number of bytes to read 
& DwNumberOfBytesRead,//the address of the number of bytes read 
NULL//non - overlapped. 
); 

if (! BTest) {
Sprintf (szMsg, "pipe. Error # % d reading", GetLastError ()); 
Printf (" % s ", szMsg); 
break; 
} 

//do something with the data. 
SzBuffer [dwNumberOfBytesRead]=0;//null terminate 
Printf (" % s ", szBuffer); 
If (' & gt; '==szBuffer] [dwNumberOfBytesRead - 1) break; 
} 

Sprintf (szMsg, "CHCP \ nexit \ n"); 
WriteFile (
HPipeInputWrite,//handle of the write end of our pipe 
& SzMsg,//address of buffer that send data 
Strlen (szMsg),//the number of bytes to write 
& DwNumberOfBytesWrite,//the address of the number of bytes read 
NULL//non - overlapped. 
); 

While (TRUE) 
{
BTest=ReadFile (
HPipeOutputRead,//handle of the read end of our pipe 
& SzBuffer,//the address of the buffer that receives the data 
256,//the number of bytes to read 
& nullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnull